I got a DGL-4100 hundred awhile ago. Threw the CD away as soon as I opened the box, same thing when I got my DIR-655.
The default IP of a Dlink router is 192.168.0.1, Username: admin, password blank.
The help link in most routers will tell you how to configure the device. the FAQs Dlink has posted are pretty helpfull as well.
then of course there is always the free support, which sometimes doesnt have the best phone connection but is pretty good for assisting with configurations for any device that says Dlink on it.
The CD is basically a Manual that allows you to click next instead of turn the page.